Recently, I'm on my computer and type startx and panels filled purple dots. How to fix it?

Note: It's now attack my CLI

Note2: I'm using Slackware

I guess you need to first determine if this is software or hardware. Certainly sounds like software, but you posted in the hardware forum and when you say CLI I'm unsure if you mean pure command line or a UI based terminal.

To diagnose hardware I'd start by viewing system settings or booting another OS and I'd check cables, and so forth. Plus I may open the system and check any internal cables/connections and flush out any dust.

For software, I still would boot an alternate OS and see if all was well somewhere else and then maybe do a parallel install of Slackware or boot it via live media and see if I could or could not duplicate it.

I install Arch Linux but not change problem

We've had purple monitor output over HDMI before, and it was due to loose/flaky connections. Sometimes just gently squeezing the HDMI connector with pliers until it visibly gets flatter has helped, but
A. This solution comes with no warranty
B. This only works with HDMI. If you don't use HDMI, don't try it.

This is obviously a hardware issue, so you could try the same monitor on another computer with the same cable, perhaps? Other than that, it could be your GPU going bad/south/out of its mind/crazy, etc.

I had a VGA display

Are you due for a hardware upgrade? More importantly, is your budget due for one?

I can't buy a new display now

My computer;
Motherboard: ASUS P4PE2-X
CPU: Intel Pentium 4
RAM: 512MB(OMG )
Monitor: Acer(I don't know model name)

Did you try the monitor in another computer? I think the GPU is more likely at fault, which is both good and bad.

If they can't buy a new display then I'd guess a new motherboard is out too.

I associate "massage" with your dead-pixel-problem because of some old magazine article that I read (for real - not a joke).
Googling around for "lcd dead pixel massage" I found these links:

http://lifehacker.com/152062/fix-your-lcds-dead-pixels

http://www.wikihow.com/Fix-a-Stuck-P...an-LCD-Monitor

http://www.pcdoctor-guide.com/wordpress/?p=2650

etc...

That's true, and I thought of that, but... the OP could get a new discrete video card and be fine. A <$20 solution. (Could be more, but I don't see a need to pay more. Anything for <$20 should be fine.)

Sorry - thought that it was a problem of the display, not of the gpu.

Sorry, I should have said who I was responding to. I was talking to rtmistler. No, your idea holds good weight too.

Try:
http://en.congelli.eu/prog_info_lcdnurse.html

In many cases you can unstick the pixel with rapidly shifting colors.